Method for generating codebook, method and apparatus for data transmission

ABSTRACT

A method for generating a codebook and a method and an apparatus for data transmission are provided. The method includes: receiving a label of a codeword sent by a User Equipment (UE); selecting the codeword identified by the label from the codebook for eight-antenna; and coding data to be sent by using the codeword. The codebook for eight-antenna includes at least one rank-8 codeword for eight-antenna. The rank-8 codeword for eight-antenna is generated by multiplying an inverse matrix of a rotation matrix for eight-antenna with an eight-dimensional matrix formed by rank-4 codewords for four-antenna; or generated by extending rank-4 codewords for eight-antenna, where the rank-4 codeword for eight-antenna is generated according to codewords for four-antenna. Therefore, the codeword in the codebook for eight-antenna is applicable to scenarios including dual-polarization strong correlation, dual-polarization weak correlation, single-polarization strong correlation, and single-polarization weak correlation, etc.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/188,325, filed Feb. 24, 2014, which is a continuation of U.S. Pat.No. 8,781,009, filed Jul. 9, 2013, which is a continuation of U.S. Pat.No. 8,509,332, filed Dec. 19, 2011, which is a continuation ofInternational Patent Application No. PCT/CN2010/074033, filed Jun. 18,2010, which claims priority to Chinese Patent Application No.200910139469.2, filed Jun. 18, 2009. The afore-mentioned patentapplications are hereby incorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to the field of communicationtechnologies, and in particular, to a method for generating a codebook,and a method and an apparatus for data transmission.

BACKGROUND OF THE INVENTION

In order to satisfy the demand of peak spectrum efficiency, support foreight antennas at a base station side is added during formulation of aLong Term Evolution Advanced (LTE-A) standard for a new generation ofwireless cellular mobile communication system.

A codebook for eight-antenna is designed by using a codebook fortwo-antenna and a codebook for four-antenna to produce a Kroneckerproduct, and use the codebook for four-antenna and the codebook fortwo-antenna to produce a Kronecker product, so as to generate a fullrank codebook C/V) for eight-antenna, which is specifically shown inFormula (1):CB ₈ ⁽⁸⁾ ⊂MCB ₈ ⁽⁸⁾ ={W ⁽²⁾

W ⁽⁴⁾ |W ^((n)) εCB _(n) ^((n)) }∪{W ⁽⁴⁾

W ⁽²⁾ |W ^((n)) εCB _(n) ^((n))}  (1)

where

${{w^{(2)} \in {CB}_{2}^{(2)}} = \left\{ {{\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\1 & {- 1}\end{bmatrix}},{\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\j & {- j}\end{bmatrix}}} \right\}},$n is equal to 2 or 4, W⁽²⁾ is a codeword in the codebook fortwo-antenna, W⁽⁴⁾ is a codeword in the codebook for four-antenna, CB₂⁽²⁾ is a full rank codebook for two-antenna, and CB₄ ⁽⁴⁾ is a full rankcodebook for four-antenna. The codeword for eight-antenna does not adaptto characteristics of a dual-polarization channel, and cannot beeffectively applied to a dual-polarization antenna.

SUMMARY OF THE INVENTION

The present invention is directed to a method for generating a codebook,and a method and an apparatus for data transmission, which areapplicable to scenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation.

Accordingly, embodiments of the present invention provide:

According to one aspect, a method for generating a codebook is provided,including:

obtaining a rotation matrix U_(rot) ⁽⁸⁾ for eight-antenna;

obtaining rank-4 codewords for four-antenna; and

obtaining a rank-8 codeword for eight-antenna by multiplying an inversematrix of the rotation matrix with an eight-dimensional matrix formed bythe rank-4 codewords for four-antenna, where the rank-8 codeword foreight-antenna is used by a base station for coding data to be sent.

According to the other aspect, a method for generating a codebook isprovided, which includes:

obtaining codewords for four-antenna; and

obtaining a rank-1 codeword for eight-antenna or a rank-4 codeword foreight-antenna by using the codewords for four-antenna.

According to another aspect, a method for data transmission is provided,which includes

receiving a label of a codeword in a codebook for eight-antenna sent bya User Equipment (UE);

selecting the codeword identified by the label from the codebook foreight-antenna; and

coding data to be sent by using the codeword, where

the codebook for eight-antenna includes at least one rank-8 codeword foreight-antenna, the rank-8 codeword being generated by multiplying aninverse matrix of a rotation matrix for eight-antenna and aneight-dimensional matrix formed by rank-4 codewords for four-antenna, orbeing generated by extending rank-4 codewords for eight-antenna, wherethe rank-4 codeword for eight-antenna is obtained according to thecodewords for four-antenna.

According to another aspect, a method for data transmission is provided,which includes:

selecting a codeword in a codebook for eight-antenna; and

sending a label of the codeword in the codebook for eight-antenna to abase station, where

the codebook for eight-antenna includes at least one rank-8 codeword foreight-antenna, the rank-8 codeword for eight-antenna being generated bymultiplying an inverse matrix of a rotation matrix for eight-antenna andan eight-dimensional matrix formed by rank-4 codewords for four-antenna,or being generated by extending rank-4 codewords for eight-antenna,where the rank-4 codeword for eight-antenna is obtained according to thecodewords for four-antenna.

According to another aspect, a base station apparatus is provided, whichincluding:

a storage unit, configured to store a codebook for eight-antenna, wherethe codebook for eight-antenna includes at least one rank-8 codeword foreight-antenna, the rank-8 codeword for eight-antenna being generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codewords forfour-antenna; or being generated by extending rank-4 codewords foreight-antenna, where the rank-4 codeword for eight-antenna is obtainedaccording to codewords for four-antenna;

a receiver, configured to receive a label of a codeword in the codebookfor eight-antenna sent by a UE;

a searching unit, configured to select the codeword identified by thelabel in the codebook for eight-antenna;

a coding unit, configured to code data to be sent by using the codewordfound by the searching unit.

According to another aspect, a user equipment (UE) is provided,including:

a storage unit, configured to store a codebook for eight-antenna, wherethe codebook for eight-antenna includes at least: a rank-8 codeword foreight-antenna, the rank-8 codeword for eight-antenna being generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codewords forfour-antenna, or being generated by extending rank-4 codewords foreight-antenna, where the rank-4 codewords for eight-antenna is obtainedaccording to codewords for four-antenna;

a selecting unit, configured to select a codeword from the codebook foreight-antenna; and

a transmitting unit, configured to send a label of the selected codewordin the codebook for eight-antenna to a base station.

According to embodiments of the present invention, the rank-8 codewordfor eight-antenna is obtained according to the rotation matrix foreight-antenna and the rank-4 codewords for four-antenna. The rank-8codeword for eight-antenna can adapt to the characteristics of adual-polarization channel, and are applicable to scenarios includingdual-polarization strong correlation, dual-polarization weakcorrelation, single-polarization strong correlation, andsingle-polarization weak correlation.

According to embodiments of the present invention, the rank-1 codewordfor eight-antenna or the rank-4 codeword for eight-antenna is obtainedby using the codewords for four-antenna. The codeword for eight-antennacan adapt to the characteristics of a dual-polarization channel, and areapplicable to scenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions according to the embodiments ofthe present invention or in the prior art more clearly, the accompanyingdrawings for describing the embodiments or the prior art are introducedbriefly in the following.

FIG. 1 is a flow chart of a method for generating a codebook accordingto Embodiment 1 of the present invention;

FIG. 2 is a flow chart of a method for generating a codebook accordingto Embodiment 2 of the present invention;

FIG. 3 is a schematic view of polarization directions of eight antennasaccording to Embodiment 2 of the present invention;

FIG. 4 is a flow chart of a method for generating a codebook accordingto Embodiment 3 of the present invention;

FIG. 5 is a flow chart of a method for generating a codebook accordingto Embodiment 4 of the present invention;

FIG. 6 is a flow chart of a method for generating a codebook accordingto Embodiment 6 of the present invention;

FIG. 7 is a flow chart of a method for generating a codebook accordingto Embodiment 7 of the present invention;

FIG. 8 is a flow chart of a method for data transmission according toEmbodiment 8 of the present invention;

FIG. 9 is a flow chart of a method for data transmission according toEmbodiment 9 of the present invention;

FIG. 10 is a flow chart of a method for data transmission according toEmbodiment 10 of the present invention;

FIG. 11 is a structural view of a base station apparatus according toEmbodiment 11 of the present invention; and

FIG. 12 is a structural view of a UE according to Embodiment 12 of thepresent invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to make the objectives, technical solutions, and advantages ofthe present invention more comprehensible, the present invention isfurther described in detail below with reference to embodiments and theaccompanying drawings. The network node in the present invention may beeNB or Relay Node (RN), and the RN or eNB is respectively taken asexamples of the network nodes for illustration below.

Embodiment 1

Embodiment 1 of the present invention provides a method for generating acodebook for eight-antenna. Referring to FIG. 1, the method includes thefollowing.

At block 101, obtain a rotation matrix for eight-antenna (8TX);

At block 102, obtain rank 4 codewords for four-antenna (4TX).

At block 103, obtain a rank-8 codeword for eight-antenna by multiplyingan inverse matrix of a rotation matrix for four-antenna with aneight-dimensional matrix formed by the rank-4 codewords forfour-antenna. The rank-8 codeword for eight-antenna are used by a basestation for coding data to be sent.

A structure of the eight-dimensional matrix formed by the rank-4codewords for four-antenna is

$\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{q}^{(4)}\end{bmatrix},{{or}\begin{bmatrix}0 & X_{q}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},{{or}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{p}^{(4)}\end{bmatrix}},{{or}\text{}\begin{bmatrix}0 & X_{p}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},$where X_(q) ⁽⁴⁾ and X_(p) ⁽⁴⁾ are respectively the rank-4 codewords forfour-antenna.

According to Embodiment 1 of the present invention, the rank-8 codewordfor eight-antenna is obtained according to the rotation matrix foreight-antenna and the rank-4 codewords for four-antenna. The rank-8codeword for eight-antenna can adapt to the characteristics of adual-polarization channel, and are applicable to scenarios includingdual-polarization strong correlation, dual-polarization weakcorrelation, single-polarization strong correlation, andsingle-polarization weak correlation.

Embodiment 2

Embodiment 2 of the present invention provides a method for generating acodebook. Referring to FIG. 2, according to this embodiment, it isassumed that transmit antennas of a base station are grouped as {1, 2,3, 4} and {5, 6, 7, 8} according to polarization directions, and thepolarization directions of the antennas at the base station side are±45° (as shown in FIG. 3); while the polarization directions ofreceiving antennas at a UE side are 0°/90°. A codeword for eight-antennais obtained by using a rotation matrix for eight-antenna and codewordsfor four-antenna, and the method specifically includes the following.

At block 201, obtain the rotation matrix for eight-antenna.

The rotation matrix for eight-antenna is

$\begin{matrix}{{U_{rot}^{(8)} = {\begin{bmatrix}1 & 0 & 0 & 0 & 1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 & 0 & 1 & 0 & 0 \\0 & 0 & 1 & 0 & 0 & 0 & 1 & 0 \\0 & 0 & 0 & 1 & 0 & 0 & 0 & 1 \\1 & 0 & 0 & 0 & {- 1} & 0 & 0 & 0 \\0 & 1 & 0 & 0 & 0 & {- 1} & 0 & 0 \\0 & 0 & 1 & 0 & 0 & 0 & {- 1} & 0 \\0 & 0 & 0 & 1 & 0 & 0 & 0 & {- 1}\end{bmatrix} = \begin{bmatrix}I_{4} & I_{4} \\I_{4} & {- I_{4}}\end{bmatrix}}},} & (2)\end{matrix}$

and a channel matrix having the polarization directions of ±45° isH_(±45)°=H_(VH)×U_(rot) ⁽⁸⁾, where H_(VH) is a channel matrix having thepolarization directions of 0°/90°.

At block 202, obtain a rank-4 codebook for four-antenna (i.e., acodebook for four antennas with rank equals 4).

It is assumed that the rank-4 codebook for four-antenna obtained in thisstep is CB⁽⁴⁾={X₁ ⁽⁴⁾, X₂ ⁽⁴⁾, . . . X_(N) ⁽⁴⁾}, where X₁ ⁽⁴⁾, X₂ ⁽⁴⁾ .. . X_(N) ⁽⁴⁾ are respectively rank-4 codewords for four-antenna.

At block 203, obtain a rank-8 codeword for eight-antenna by multiplyinga reverse matrix of a rotation matrix for four-antenna with aneight-dimensional matrix formed by the rank-4 codewords forfour-antenna.

A structure of the eight-dimensional matrix formed by the rank-4codewords for four-antenna is

$\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{q}^{(4)}\end{bmatrix},{{or}\mspace{20mu}\begin{bmatrix}0 & X_{q}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},{{or}\mspace{14mu}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{p}^{(4)}\end{bmatrix}},{{or}\begin{bmatrix}0 & X_{p}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},$where X_(q) ⁽⁴⁾ and X_(p) ⁽⁴⁾ are respectively the rank-4 codewords forfour-antenna.

Specifically, according to this step, the rank-8 codeword foreight-antenna can be obtained through the following Formula (3) orFormula (4):

$\begin{matrix}{W_{m}^{(8)} = {{\left( U_{rot}^{(8)} \right)^{- 1}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{q}^{(4)}\end{bmatrix}} = {{\begin{bmatrix}I_{4} & I_{4} \\I_{4} & {- I_{4}}\end{bmatrix}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{q}^{(4)}\end{bmatrix}} = \begin{bmatrix}X_{p}^{(4)} & X_{q}^{(4)} \\X_{p}^{(4)} & {- X_{q}^{(4)}}\end{bmatrix}}}} & (3) \\{W_{m}^{(8)} = {{\left( U_{rot}^{(8)} \right)^{- 1}\begin{bmatrix}0 & X_{q}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}} = {{\begin{bmatrix}I_{4} & I_{4} \\I_{4} & {- I_{4}}\end{bmatrix}\begin{bmatrix}0 & X_{q}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}} = \begin{bmatrix}X_{p}^{(4)} & X_{q}^{(4)} \\{- X_{p}^{(4)}} & X_{q}^{(4)}\end{bmatrix}}}} & (4)\end{matrix}$

where W_(m) ⁽⁸⁾ is an m^(th) codeword in a rank-8 codebook foreight-antenna, and

X_(p) ⁽⁴⁾ and X_(q) ⁽⁴⁾ are respectively codewords in the rank-4codebook for four-antenna.

Alternatively, W_(m) ⁽⁸⁾ may also be obtained through the followingformula

${W_{m}^{(8)} = {{\left( U_{rot}^{(8)} \right)^{- 1}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{p}^{(4)}\end{bmatrix}}\mspace{14mu}{or}}}\mspace{20mu}$${W_{m}^{(8)} = {\left( U_{rot}^{(8)} \right)^{- 1}\begin{bmatrix}0 & X_{p}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}}},$and the implementation of the present invention is not affected.

It should be noted that, the codeword in other polarization groupings ofantennas may be obtained by switching rows of the rank-8 codeword foreight-antenna obtained in this step; and the codeword is not changed bymultiplying rows or columns of the rank-8 codeword for eight-antennawith a scalar.

According to Embodiment 2 of the present invention, the rank-8 codewordfor eight-antenna is obtained according to the rotation matrix foreight-antenna and the rank-4 codewords for four-antenna. The rank-8codeword for eight-antenna is based on the rank-4 codewords forfour-antenna, so that the complexity of the codebook design issimplified. The codeword for eight-antenna obtained through theembodiment of the present invention has a nested characteristic and afinite character set, which may decrease the computational complexity ofa Channel Quality Indicator (CQI) and reduce the storage space of a basestation and a UE. The codeword for eight-antenna may be applicable toscenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation, etc.

Embodiment 3

Embodiment 3 of the present invention provides a method for generating acodebook. Referring to FIG. 4, the method includes the following.

At block 401, obtain a codeword for four-antenna.

At block 402, obtain one or more rank-1 codeword for eight-antenna orone or more rank-4 codeword for eight-antenna by using the codewords forfour-antenna.

According to Embodiment 3 of the present invention, the rank-1 codewordfor eight-antenna or the rank-4 codeword for eight-antenna is directlyobtained by using the codeword for four-antenna, which simplifies thecomplexity of the codebook design, and may be applicable to scenariosincluding dual-polarization strong correlation, dual-polarization weakcorrelation, single-polarization strong correlation, andsingle-polarization weak correlation, etc.

Embodiment 4

Embodiment 4 of the present invention provides a method for generating acodebook. Referring to FIG. 5, in this method, obtaining rank-1 codewordfor eight-antenna by using a codeword for four-antenna, obtaining arank-4 codeword for eight-antenna by using the rank-1 codeword foreight-antenna, and obtaining a rank-8 codeword for eight-antenna byextending the rank-4 codeword for eight-antenna. This methodspecifically includes the following.

At block 501, determine a size P of a codebook for eight-antennacodebook according to design requirements.

The size of the codebook for eight-antenna is the number of thecodewords in the codebook for eight-antenna.

At block 502, determine that the number of the codewords optimized for ascenario of single-polarization strong correlation is Q, and that thenumber of the codewords optimized for a scenario of dual-polarizationstrong correlation is R, where Q+R<P.

At block 503, obtain the rank-1 codeword for eight-antenna optimized forthe scenario of single-polarization strong correlation and the rank-1codeword for eight-antenna optimized for the scenario ofdual-polarization strong correlation, and delete a repeated codeword inthe rank-1 codeword eight-antenna optimized for the scenario ofsingle-polarization strong correlation and the eight-antenna rank-1codeword optimized for the scenario of dual-polarization strongcorrelation.

Specifically, a process for determining the eight-antenna rank-1codeword optimized for the scenario of single-polarization strongcorrelation specifically includes the following.

(1) Discrete Fourier Transformation (DFT) based rank-1 codewords forfour transmit antennas (also referred to as DFT based rank-1 codewordsfor four-antenna) having a size of Q are generated by using Formula (5):

$\begin{matrix}{D_{g,{mn}}^{(N_{T})} = {{\exp\left( {j\frac{2\pi}{N_{T}}{m\left( {n + \frac{g}{Q}} \right)}} \right)}\text{/}N_{T}}} & (5)\end{matrix}$

where N_(T) is the number of 4 of the transmit antennas, and D_(g,mn)^((N) ^(T) ⁾ is an element of an m^(th) row and an n^(th) column of ag^(th) codeword in the codebook.

(2) The rank-1 codeword for eight-antenna is obtained by multiplying theDFT based rank-1 codeword for four transmit antennas v_(p) ⁽⁴⁾ with anoptimized parameter e^(jθ) ^(p) , and then concatenating the DFT basedrank-1 codeword for four transmit antennas v_(p) ⁽⁴⁾ and a matrixobtained by the multiplication.

The rank-1 codeword for eight-antenna is obtained by using Formulas (6)and (7):

$\begin{matrix}{{u_{p}^{(8)} = \begin{bmatrix}v_{p}^{(4)} & \; \\{{\mathbb{e}}^{j\;\theta_{p}}v_{p}^{(4)}} & \;\end{bmatrix}},{p \in \left\{ {1,2,{\ldots\; Q}} \right\}}} & (6)\end{matrix}$

where the optimized parameter

$\begin{matrix}{{{\mathbb{e}}^{j\;\theta_{p}} = \left( \frac{v_{p}^{4}(2)}{v_{p}^{4}(1)} \right)^{4}},} & (7)\end{matrix}$

and where v_(p) ⁽⁴⁾ represents the DFT based rank-1 codeword for fourtransmit antennas obtained according to D_(g,mn) ^((N) ^(T) ⁾.

As for scenarios of dual-polarization correlation, in this embodiment,it is assumed that polarization directions of the antennas at a basestation side are ±45°, and the polarization directions of receivingantennas at a UE side are 0°/90°. Specifically, a process fordetermining the rank-1 codeword for eight-antenna optimized for thescenario of dual-polarization strong correlation includes the following.

(1) Rank-4 codewords for four transmit antenna are obtained throughfollowing:

$\begin{matrix}{{M_{r}^{(4)} = \begin{bmatrix}1 & 0 & 1 & 0 \\\alpha_{r} & 0 & {- \alpha_{r}} & 0 \\0 & 1 & 0 & 1 \\0 & \beta_{r} & 0 & {- \beta_{r}}\end{bmatrix}},{r = 1},2,{\ldots\; R\text{/}2}} & (8) \\{{{M_{r}^{(4)} = \begin{bmatrix}0 & 1 & 0 & 1 \\0 & \beta_{r - {R/2}} & 0 & {- \beta_{r - {R/2}}} \\1 & 0 & 1 & 0 \\\alpha_{r - {R/2}} & 0 & {- \alpha_{r - {R/2}}} & 0\end{bmatrix}},{r = {{R\text{/}2} + 1}},{\ldots\; R}}{where}{\alpha_{r},{{\beta_{r} \in \Psi_{M}} = {\left\{ {{\left. {\mathbb{e}}^{j\frac{2\pi}{M}m} \middle| m \right. = 0},1,{{\ldots\; M} - 1}} \right\}.}}}} & (9)\end{matrix}$the rank-4 codewords for four transmit antenna obtained in this stepneed to ensure that a matrix obtained by switching a second column witha third column in M_(r) ⁽⁴⁾ is a block diagonal matrix.

(2) If the polarization groupings of antennas are {1, 2, 5, 6} and {3,4, 7, 8}, the rank-1 codeword for eight-antenna is obtained by usingFormula (10). If the polarization groupings of antennas are {1, 2, 7, 8}and {3, 4, 5, 6}, the rank-1 codeword for eight-antenna is obtained byusing Formula (11).

When the polarization groupings of antennas are {1, 2, 5, 6} and {3, 4,7, 8}, a matrix having four rows and one column is obtained bymultiplying a rotation matrix for four-antenna with a first column ofM_(r) ⁽⁴⁾. The matrix having four rows and one column is multiplied withan optimized parameter e^(jθ) ^(r) to generate a matrix. The rank-1codeword for eight-antenna is obtained by concatenating the matrixgenerated by multiplying the matrix having four rows and one column withthe optimized parameter e^(jθ) ^(r) , and the matrix having four rowsand one column:

$\begin{matrix}{{{u_{r}^{(8)} = \begin{bmatrix}{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,1}} \right)}} & \; \\{{\mathbb{e}}^{j\;\theta_{r}}U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,1}} \right)}} & \;\end{bmatrix}},{r \in \left\{ {1,2,{\ldots\; R}} \right\}}}{{{{where}\mspace{14mu} U_{rot}^{(4)}} = \begin{bmatrix}1 & 0 & 1 & 0 \\0 & 1 & 0 & 1 \\1 & 0 & {- 1} & 0 \\0 & 1 & 0 & {- 1}\end{bmatrix}},{and}}{{\mathbb{e}}^{j\;\theta_{r}} = \left\{ \begin{matrix}\left( \alpha_{r} \right)^{2} & {{r = 1},2,{\ldots\;{R/2}}} \\\left( \alpha_{r - {R/2}} \right)^{2} & {{r = {{R\text{/}2} + 1}},{\ldots\;{R.}}}\end{matrix} \right.}} & (10)\end{matrix}$

When the polarization groupings of antennas are {1, 2, 7, 8} and {3, 4,5, 6}, a first matrix is obtained by multiplying a rotation matrix forfour-antenna with a first column of M_(r) ⁽⁴⁾, if r is in a range of 1to R/2, a second matrix is obtained by multiplying the rotation matrixfor four-antenna with a first column of M_(r+R/2) ⁽⁴⁾ and the optimizedparameter e^(jθ) ^(r) , and the eight-antenna rank-1 codeword isobtained by concatenating the first matrix and the second matrix; whileif r is in a range of (R/2)+1 to R, a third matrix is obtained bymultiplying a rotation matrix for four-antenna with a first column ofM_(r−R/2) ⁽⁴⁾ and the optimized parameter e^(jθ) ^(r) , and theeight-antenna rank-1 codeword is obtained by concatenating the firstmatrix and the third matrix:

$\begin{matrix}{{{u_{r}^{(8)} = \begin{bmatrix}{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,1}} \right)}} & \; \\{{\mathbb{e}}^{j\;\theta_{r}}U_{rot}^{(4)}{M_{r + {R/2}}^{(4)}\left( {:{,1}} \right)}} & \;\end{bmatrix}},{r \in \left\{ {1,2,{\ldots\; R\text{/}2}} \right\}}}{{u_{r}^{(8)} = \begin{bmatrix}{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,1}} \right)}} & \; \\{{\mathbb{e}}^{j\;\theta_{r}}U_{rot}^{(4)}{M_{r - {R/2}}^{(4)}\left( {:{,1}} \right)}} & \;\end{bmatrix}},{r \in \left\{ {{{R\text{/}2} + 1},{\ldots\; R}} \right\}}}{{{{where}\mspace{14mu} U_{rot}^{(4)}} = \begin{bmatrix}1 & 0 & 1 & 0 \\0 & 1 & 0 & 1 \\1 & 0 & {- 1} & 0 \\0 & 1 & 0 & {- 1}\end{bmatrix}},{and}}{{\mathbb{e}}^{j\;\theta_{r}} = \left\{ \begin{matrix}\left( \alpha_{r} \right)^{2} & {{r = 1},2,{\ldots\; R\text{/}2}} \\\left( \alpha_{r - {R/2}} \right)^{2} & {{r = {{R\text{/}2} + 1}},{\ldots\;{R.}}}\end{matrix} \right.}} & (11)\end{matrix}$

It should be noted that, a definition for repeated rank-1 codeword isthat if a codeword a can be written as a codeword b multiplied with ascalar c, that is, a=b·c, the codeword a is repeated with the codewordc.

At block 504, obtain the rank-1 codeword for eight-antenna optimized fora scenario of dual-polarization weak correlation.

It is assumed that, at block 503, the number of repeated codewords ofthe rank-1 codewords for eight-antenna optimized for the scenario ofsingle-polarization strong correlation and the rank-1 codewords foreight-antenna optimized for the scenario of dual-polarization strongcorrelation is S, so that the number of the rank-1 codewords foreight-antenna optimized for the scenario of dual-polarization weakcorrelation is P−(Q+R)+S.

As for the scenario of dual-polarization weak correlation, a fourthmatrix is obtained by multiplying a rotation matrix for four-antennawith a first column of M_(r1) ⁽⁴⁾, a fifth matrix is obtained bymultiplying the rotation matrix for four-antenna with a first column ofM_(r2) ⁽⁴⁾ and an optimized parameter e^(jθ) ^(t) , and the rank-1codeword for eight-antenna is obtained by concatenating the fourthmatrix and the fifth matrix.

If the polarization groupings of antennas are {1, 2, 5, 6} and {3, 4, 7,8}, the rank-1 codeword for eight-antenna is obtained by using thefollowing Formula (12):

$\begin{matrix}{{u_{t}^{(8)} = \begin{bmatrix}{U_{rot}^{(4)}{M_{r\; 1}^{(4)}\left( {:{,1}} \right)}} \\{{\mathbb{e}}^{j\;\theta_{t}}U_{rot}^{(4)}{M_{r\; 2}^{(4)}\left( {:{,1}} \right)}}\end{bmatrix}}{{t \in \left\{ {1,2,{{\ldots\; P} - Q - R + S}} \right\}},{{r\; 1} \neq {r\; 2}},{r\; 1},{{r\; 2} \in {\left\{ {1,2,{\ldots\; R\text{/}2}} \right\}\bigcup{r\; 1}}},{{r\; 2} \in {\left\{ {{{R\text{/}2} + 1},{\ldots\; R}} \right\}.}}}} & (12)\end{matrix}$

If the polarization groupings of antennas are {1, 2, 7, 8} and {3, 4, 5,6}, rank-1 codeword for eight-antenna is obtained by using the followingFormula (13):

$\begin{matrix}{{u_{t}^{(8)} = \begin{bmatrix}{U_{rot}{M_{r\; 1}^{(4)}\left( {:{,1}} \right)}} \\{{\mathbb{e}}^{j\;\theta_{t}}U_{rot}{M_{r\; 2}^{(4)}\left( {:{,1}} \right)}}\end{bmatrix}}{{t \in \left\{ {1,2,{{\ldots\; P} - Q - R + S}} \right\}},{{{{r\; 1} - {r\; 2}}} \neq {R\text{/}2}},{{r\; 1} \in {\left\{ {1,2,{\ldots\; R\text{/}2}} \right\}\bigcap{r\; 2}} \in {\left\{ {{{R\text{/}2} + 1},{\ldots\; R}} \right\}\bigcup{r\; 1}} \in {\left\{ {{{R\text{/}2} + 1},{\ldots\; R}} \right\}\bigcap{r\; 2}} \in \left\{ {1,2,{\ldots\; R\text{/}2}} \right\}}}} & (13)\end{matrix}$

At block 505, generate a rank-4 codeword for eight-antenna according toa rank-4 codeword for four-antenna generated by extending a rank-1codeword for four-antenna in first four rows of the rank-1 codeword foreight-antenna, and a rank-4 codeword for four-antenna generated byextending a rank-1 codeword for four-antenna in last four rows of therank-1 codeword for eight-antenna and then multiplied with a diagonalmatrix.

(1) As for the scenario of single-polarization strong correlation, thefollowing two manners may be adopted to obtain the rank-4 codeword forfour-antenna M_(p).

A first manner is that a rank-4 codeword for four-antenna M_(p) isgenerated by performing Householder transformation on a rank-1 codewordfor four-antenna (as shown in Formula (13a)):

$\begin{matrix}{M_{p} = {\begin{bmatrix}1 & 0 & 0 & 0 \\0 & {- 1} & 0 & 0 \\0 & 0 & {- 1} & 0 \\0 & 0 & 0 & {- 1}\end{bmatrix}v_{p}^{(4)}}} & \left( {13a} \right)\end{matrix}$

where v_(p) ⁽⁴⁾ represents the rank-1 codeword for four-antenna.

A second manner is that a rank-4 codeword for four-antenna M_(p) isgenerated by using the following Formula (13b) and taking Formula (13c)as a constraint condition:M _(p) =e _(p) ·T  (13b)

where e_(p) is a diagonal matrix, e_(p) is relevant to v_(p) ⁽⁴⁾, andv_(p) ⁽⁴⁾ is a first column of M_(p) (see Formula (13c)):v _(p) ⁽⁴⁾ =M _(p)(:,1)  (13c)

where T is any 4×4-dimensional Unitary matrix (such as a DFT matrix).

As for the scenario of dual-polarization strong correlation, a rank-1codeword for four-antenna in a rank-1 codeword for eight-antenna isextended to generate a rank-4 codeword for four-antenna, as shown inFormula (14):U _(rot) M _(r) ⁽⁴⁾(:,1)→U _(rot) M _(r) ⁽⁴⁾(:,1:4)  (14).

(2) Multiplying a rank-4 codeword for four-antenna obtained by extendingthe rank-1 codeword for four-antenna in last four rows of a rank-1codeword for eight-antenna with a diagonal matrix, so as to obtain arank-4 codeword for eight-antenna.

The following matrix is the rank-4 codeword for eight-antenna optimizedfor the scenario of single-polarization strong correlation:

$\begin{bmatrix}M_{p}^{(4)} \\{M_{p}^{(4)}\Lambda_{p}}\end{bmatrix}.$

The following matrix is the rank-4 codeword for eight-antenna optimizedfor the scenario of dual-polarization strong correlation when thepolarization groupings of antennas are {1, 2, 5, 6} and {3, 4, 7, 8}:

$\begin{bmatrix}{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}} \\{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}\Lambda_{r}}\end{bmatrix}.$

The following matrix is the rank-4 codeword for eight-antenna optimizedfor the scenario of dual-polarization weak correlation:

$\quad\begin{bmatrix}{U_{rot}^{(4)}{M_{r\; 1}^{(4)}\left( {:{,{1:4}}} \right)}} \\{U_{rot}^{(4)}{M_{r\; 2}^{(4)}\left( {:{,{1:4}}} \right)}\Lambda_{t}}\end{bmatrix}$

where Λ is the diagonal matrix used for optimizing a code distance of ahigh rank (that is, the rank >1), and Λ(1,1)=e^(jθ) is already set anddetermined by a rank-1 codeword optimizing process; Λ(2, 2) may bedetermined through directivity, or may be obtained by optimizing achordal distance of rank-2 codewords.

At block 506, generate a rank-8 codeword for eight-antenna by extendingthe rank-4 codewords for eight-antenna. Orthogonality of the codewordsin a rank-8 codebook for eight-antenna is ensured.

Specific implementation manner of this step may be: using the rank-4codeword for eight-antenna as first four columns of the rank-8 codewordfor eight-antenna, and using negative values of first four rows or lastfour rows of the rank-4 codeword for eight-antenna as last four columnsof the rank-8 codeword for eight-antenna; or, using the rank-4 codewordfor eight-antenna as last four columns of the rank-8 codeword foreight-antenna, and using negative values of first four rows or last fourrows of the rank-4 codeword for eight-antenna as first four columns ofthe rank-8 codeword for eight-antenna.

The rank-8 codeword for eight-antenna optimized for the scenario ofsingle-polarization strong correlation may form the following matrix:

$\begin{bmatrix}M_{p}^{(4)} & M_{p}^{(4)} \\{M_{p}^{(4)}\Lambda_{p}} & {{- M_{p}^{(4)}}\Lambda_{p}}\end{bmatrix}.$

When the polarization groupings of antennas are {1, 2, 5, 6} and {3, 4,7, 8}, the rank-8 codeword for eight-antenna optimized for the scenarioof dual-polarization strong correlation may form the following matrix:

$\begin{bmatrix}{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}} & {U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}} \\{U_{rot}^{(4)}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}\Lambda_{r}} & {{- U_{rot}^{(4)}}{M_{r}^{(4)}\left( {:{,{1:4}}} \right)}\Lambda_{r}}\end{bmatrix}.$

The rank-8 codeword for eight-antenna optimized for the scenario ofdual-polarization weak correlation may form the following matrix:

$\begin{bmatrix}M_{p}^{(4)} & M_{p}^{(4)} \\{M_{p}^{(4)}\Lambda_{p}} & {{- M_{p}^{(4)}}\Lambda_{p}}\end{bmatrix}.$

In the above embodiment, the rank-1 codeword for eight-antenna is thecodeword for eight antennas with the rank of 1, the rank-4 codeword foreight-antenna is the codeword for eight antennas with the rank of 4, therank-8 codeword for eight-antenna is the codeword for eight antennaswith the rank of 8, the rank-1 codeword for four-transmit-antenna is thecodeword for four transmit antennas with the rank of 1, and the rank-4codeword for four-transmit-antenna is the codeword for four transmitantennas with the rank of 4.

According to Embodiment 4 of the present invention, generate the rank-1codeword for eight-antenna by using the rank-4 codewords forfour-antenna, and generate the rank-4 codewords for eight-antenna, andthen generate a rank-8 codeword for eight-antenna by extending therank-4 codewords for eight-antenna. The codeword for eight-antenna isgenerated based on the codeword for four-antenna, thereby simplifyingthe complexity of the codebook design. The codeword for eight-antennahas a nested characteristic and a finite character set, which maydecrease the computational complexity of a CQI. The codeword foreight-antenna is applicable to scenarios including dual-polarizationstrong correlation, dual-polarization weak correlation,single-polarization strong correlation, and single-polarization weakcorrelation, etc.

Embodiment 5

Embodiment 5 of the present invention provides a method for generating acodebook, and a difference of this method from Embodiment 4 is asfollows.

A design method of eight-antenna rank-1 codewords optimized for ascenario of single-polarization strong correlation is different, and aspecific design process includes the following.

DFT based rank-1 codeword for eight transmit antennas x_(p) ⁽⁸⁾ having asize of Q is generated first, where pε{1, 2, . . . Q}. Formula (5) maybe employed for implementation, and at this time, N_(T) in Formula (5)is 8.

Rank-1 codeword for four-antenna v_(p) ⁽⁴⁾ is obtained by using thefollowing formula:

${v_{p}^{(4)} = \begin{bmatrix}{x_{p}^{(8)}\left( {1:2} \right)} \\{x_{p}^{(8)}\left( {5:6} \right)}\end{bmatrix}},{p \in {\left\{ {1,2,{\ldots\mspace{14mu} Q}} \right\}.}}$

The rank-1 codeword for eight-antenna is generated by concatenating androtating the codeword for four-antenna, and a specific implementationmanner may use the following formula:

${u_{p}^{(8)} = \begin{bmatrix}v_{p}^{(4)} \\{{\mathbb{e}}^{j\;\theta_{p}}v_{p}^{(4)}}\end{bmatrix}},{p \in \left\{ {1,2,{\ldots\mspace{14mu} Q}} \right\}},{where}$${\mathbb{e}}^{j\;\theta_{p}} = {\left( \frac{v_{p}^{4}(2)}{v_{p}^{4}(1)} \right)^{2}.}$

According to the embodiment of the present invention, polarizationgroupings of antennas are {1, 2, 3, 4} and {5, 6, 7, 8}; therefore, athird row and a fourth row of the rank-8 codeword for eight-antennagenerated from Embodiment 2 are switched with a fifth row and a sixthrow, and reference is made to the following formula:

$W_{(i)}^{(8)} = {\Pi\begin{bmatrix}M_{i}^{(4)} & M_{i}^{(4)} \\{M_{i}^{(4)}\Lambda_{i}} & {{- M_{i}^{(4)}}\Lambda_{i}}\end{bmatrix}}$ where $\Pi = {\begin{bmatrix}1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 \\0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 \\0 & 0 & 0 & 0 & 0 & 0 & 0 & 1\end{bmatrix}.}$

According to Embodiment 5 of the present invention, generate the rank-1codeword for eight-antenna by using the four-antenna rank-4 codeword,and generate the rank-4 codeword for eight-antenna, and then generatethe rank-8 codeword for eight-antenna by extending the rank-4 codewordsfor eight-antenna. The codeword for eight-antenna is based on thecodeword for four-antenna, thereby simplifying the complexity of thecodebook design. The codeword for eight-antenna has a nestedcharacteristic and a finite character set, which may decrease thecomputational complexity of a CQI and reduce the storage space of a basestation and a UE. The codeword for eight-antenna is applicable toscenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation, etc.

Embodiment 6

Embodiment 6 of the present invention provides a method for generating acodebook, which is applicable to a scenario of single-polarizationstrong correlation. Referring to FIG. 6, a rank-4 codeword foreight-antenna is directly obtained from a rank-4 codeword forfour-antenna according to this embodiment. The method specificallyincludes the following.

At block 601, as for the scenario of single-polarization strongcorrelation, DFT based rank-1 codeword for four transmit antennas isgenerated, and a rank-4 codeword for four-antenna is generated accordingto the DFT based rank-1 codeword for four transmit antennas.

A manner for generating the DFT based rank-1 codewords for four transmitantennas having a size of Q may use Formula (5), and a manner forobtaining the rank-4 codewords for four-antenna according to the DFTbased rank-1 codewords for four transmit antennas may use Formula (13a)or Formulas (13b) and (13c).

At block 602, the rank-4 codeword for four-antenna is multiplied by adiagonal matrix, and the rank-4 codeword for eight-antenna is generatedby concatenating the rank-4 codeword for four-antenna and a matrixobtained by multiplying the rank-4 codeword for four-antenna with thediagonal matrix.

A structure of the rank-4 codeword for eight-antenna may be

$\begin{bmatrix}M_{p}^{(4)} \\{M_{p}^{(4)}\Lambda_{p}}\end{bmatrix},$

where Λ_(p) is the diagonal matrix, p represents that the rank-4codeword for eight-antenna is a p^(th) codeword in a rank-4 codebook foreight-antenna, and M_(P) ⁽⁴⁾ represents the rank-4 codeword forfour-antenna.

Alternatively, in this step, a first rank-4 codeword for four-antenna ismultiplied by the diagonal matrix, and the rank-4 codeword foreight-antenna is obtained by concatenating a second rank-4 codeword forfour-antenna and a matrix obtained by multiplying the first four-antennarank-4 codeword with the diagonal matrix.

At block 603, the rank-4 codeword for eight-antenna is used as firstfour columns of rank-8 codeword for eight-antenna, and negative valuesof first four rows or last four rows of the rank-4 codeword foreight-antenna are used as last four columns of the rank-8 codeword foreight-antenna; or, the rank-4 codeword for eight-antenna is used as lastfour columns of the rank-8 codeword for eight-antenna, and negativevalues of first four rows or last four rows of the rank-4 codeword foreight-antenna are used as first four columns of the rank-8 codeword foreight-antenna.

According to Embodiment 6 of the present invention, generate the rank-4codeword for four-antenna according to the DFT based rank-1 codeword forfour transmit antennas, then generate the rank-4 codeword foreight-antenna according to the rank-4 codeword for four-antenna, andgenerate rank-8 codeword for eight-antenna by extending the rank-4codewords for eight-antenna. The codeword for eight-antenna is based onthe codeword for four-antenna, thereby simplifying the complexity of thecodebook design. The codeword for eight-antenna has a nestedcharacteristic and a finite character set, which may decrease thecomputational complexity of a CQI. The codeword for eight-antenna isapplicable to scenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation, etc.

Embodiment 7

Embodiment 7 of the present invention provides a method for generating acodebook, which is applicable to scenarios of single-polarizationcorrelation and dual-polarization correlation. Referring to FIG. 7, arank-4 codeword for eight-antenna is directly generated from rank-4codewords for four-antenna according to this method, and this methodspecifically includes the following.

At block 701, obtain a rank-4 codebook for four-antenna.

A structure of the rank-4 codebook for four-antenna is as follows:CB ⁽⁴⁾ ={X ₁ ⁽⁴⁾ ,X ₂ ⁽⁴⁾ , . . . X _(N) ⁽⁴⁾}.

At block 702, a first codeword (that is, a first rank-4 codeword forfour-antenna) in the rank-4 codebook for four-antenna is multiplied by adiagonal matrix, and the rank-4 codeword for eight-antenna is generatedby concatenating a matrix obtained by multiplying the first codeword inthe rank-4 codebook for four-antenna with the diagonal matrix and asecond codeword in the rank-4 codebook for four-antenna. In this step,said a first codeword and said a second codeword do not represent thefirst codeword and the second codeword (that is, a second rank-4codeword for four-antenna) in the four-antenna rank-4 codebook, butrepresent two different codewords in the rank-4 codebook forfour-antenna.

At block 703, the rank-4 codeword for eight-antenna is used as firstfour columns of rank-8 codeword for eight-antenna, and negative valuesof first four rows or last four rows of the rank-4 codeword foreight-antenna are used as last four columns of the rank-8 codeword foreight-antenna; or, the rank-4 codeword for eight-antenna is used as lastfour columns of rank-8 codeword for eight-antenna, and negative valuesof first four rows or last four rows of the rank-4 codeword foreight-antenna are used as first four columns of the rank-8 codeword foreight-antenna, and a structure of the generated rank-8 codeword foreight-antenna is as follows:

${W_{m}^{(8)} = \begin{bmatrix}X_{p}^{(4)} & X_{p}^{(4)} \\{X_{q}^{(4)}\Lambda_{m}} & {{- X_{q}^{(4)}}\Lambda_{m}}\end{bmatrix}},{p \in 1},2,{\ldots\mspace{14mu} N},{q \in 1},2,{\ldots\mspace{14mu} N},.$

In the above step 702, a codeword in the rank-4 codebook forfour-antenna is multiplied by the diagonal matrix, and the rank-4codeword for eight-antenna is generated by concatenating a matrixobtained through the multiplication and the same codeword. A matrixstructure of a generated rank-8 codebook for eight-antenna is asfollows:

${W_{m}^{(8)} = \begin{bmatrix}X_{p}^{(4)} & X_{p}^{(4)} \\{X_{p}^{(4)}\Lambda_{m}} & {{- X_{p}^{(4)}}\Lambda_{m}}\end{bmatrix}},{p \in 1},2,{\ldots\mspace{14mu} N},{q \in 1},2,{\ldots\mspace{14mu} N},.$

According to Embodiment 7 of the present invention, the rank-4 codewordfor eight-antenna is generated by using the rank-4 codeword forfour-antenna, and the rank-4 codewords for eight-antenna is extended togenerate the rank-8 codeword for eight-antenna. The codeword foreight-antenna is based on the codewords for four-antenna, therebysimplifying the complexity of the codebook design. The codeword foreight-antenna has a nested characteristic and a finite character set,which may decrease the computational complexity of a CQI and reduce thestorage space of a base station and a UE. The codeword for eight-antennais applicable to scenarios including dual-polarization strongcorrelation, dual-polarization weak correlation, single-polarizationstrong correlation, and single-polarization weak correlation, etc.

In order to make the embodiment of the present invention morecomprehensible, an example is given below for illustration.

It is assumed that a character set is

${\Psi = \left\{ {{\pm 1},{\pm j},{\pm \frac{1 + j}{\sqrt{2}}},{\pm \frac{1 - j}{\sqrt{2}}}} \right\}},$all elements of codewords in the eight-antenna codebook are the elementsin the character set. It is assumed that the number of codewords in thecodebook is N=16.

It is assumed that polarization groupings of antennas are {1, 2, 3, 4}and {5, 6, 7, 8}, and a downlink MIMO codebook for eight-antennaobtained after a chordal distance optimization by using the technicalsolutions provided by the embodiment of the present invention is asfollows:

$W_{i} = {\frac{1}{\sqrt{2}}{\Pi\begin{bmatrix}M_{i}^{(4)} & M_{i}^{(4)} \\{M_{i}^{(4)}\Lambda_{i}} & {{- M_{i}^{(4)}}\Lambda_{i}}\end{bmatrix}}}$ where ${\Pi = \begin{bmatrix}1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 \\0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 \\0 & 0 & 0 & 0 & 0 & 0 & 0 & 1\end{bmatrix}},{M_{i}^{(4)} = {I_{4} - {2\; u_{i}{u_{i}^{H}/u_{i}^{H}}{u_{i}.}}}}$

The generated vector u_(i) and diagonal matrix Λ_(i) are as shown inTable 1.

TABLE 1 Index u_(i) Λ_(i) 0 u₀ = [1 −1 −1 −1]^(T) diag{[1 1 −1 j]} 1 u₁= [1 −1 1 1]^(T) diag{[1 1 −1 1]} 2 u₂ = [1 −j −1 −j]^(T)diag{[−1 −j 1 j]} 3 u₃ = [1 −j 1 j]^(T) diag{[−1 −1 1 j]} 4 u₄ =[1 1 −1 1]^(T) diag{[1 1 1 1]} 5 u₅ = [1 1 1 −1]^(T) diag{[1 1 −j j]} 6u₆ = [1 j −1 j]^(T) diag{[−1 −1 1 j]} 7 u₇ = [1 j 1 −j]^(T)diag{[−1 −1 −j −j]} 8 $u_{8} = \begin{bmatrix}1 & {- \frac{1 + j}{\sqrt{2}}} & 1 & \frac{1 + j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[j j −j −1]} 9 $u_{9} = \begin{bmatrix}1 & {- \frac{1 + j}{\sqrt{2}}} & {- 1} & {- \frac{1 + j}{\sqrt{2}}}\end{bmatrix}^{T}$ diag{[j j 1 −j]} 10 $u_{10} = \begin{bmatrix}1 & \frac{1 - j}{\sqrt{2}} & 1 & \frac{{- 1} + j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[−j 1 j j]} 11 $u_{11} = \begin{bmatrix}1 & \frac{1 - j}{\sqrt{2}} & {- 1} & \frac{1 - j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[−j −j −j j]} 12 $u_{12} = \begin{bmatrix}1 & \frac{1 + j}{\sqrt{2}} & 1 & \frac{{- 1} - j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[j j j −j]} 13 $u_{13} = \begin{bmatrix}1 & \frac{1 + j}{\sqrt{2}} & {- 1} & \frac{1 + j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[j j −1 −j]} 14 $u_{14} = \begin{bmatrix}1 & \frac{{- 1} + j}{\sqrt{2}} & 1 & \frac{1 - j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[−j 1 j −j]} 15 $u_{15} = \begin{bmatrix}1 & \frac{{- 1} + j}{\sqrt{2}} & {- 1} & \frac{{- 1} + j}{\sqrt{2}}\end{bmatrix}^{T}$ diag{[−j −j j 1]}

A mapping relation between the rank-8 codewords and other rank codewordsis as shown in Table 2.

TABLE 2 Number of layers ν PMI 1 2 3 4 5 6 7 8 0 W₀ ^({1})$\frac{W_{0}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{0}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{0}^{\{ 1345\}}}{2}$ $\frac{W_{0}^{\{ 13456\}}}{\sqrt{5}}$$\frac{W_{0}^{\{ 134562\}}}{\sqrt{6}}$$\frac{W_{0}^{\{ 1345627\}}}{\sqrt{7}}$$\frac{W_{0}^{\{ 13456278\}}}{\sqrt{8}}$ 1 W₁ ^({1})$\frac{W_{1}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{1}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{1}^{\{ 1235\}}}{2}$ $\frac{W_{1}^{\{ 12356\}}}{\sqrt{5}}$$\frac{W_{1}^{\{ 123564\}}}{\sqrt{6}}$$\frac{W_{1}^{\{ 1235647\}}}{\sqrt{7}}$$\frac{W_{1}^{\{ 12356478\}}}{\sqrt{8}}$ 2 W₂ ^({1})$\frac{W_{2}^{\{ 14\}}}{\sqrt{2}}$ $\frac{W_{2}^{\{ 143\}}}{\sqrt{3}}$$\frac{W_{2}^{\{ 1435\}}}{2}$ $\frac{W_{2}^{\{ 14352\}}}{\sqrt{5}}$$\frac{W_{2}^{\{ 143528\}}}{\sqrt{6}}$$\frac{W_{2}^{\{ 1435287\}}}{\sqrt{7}}$$\frac{W_{2}^{\{ 14352876\}}}{\sqrt{8}}$ 3 W₃ ^({1})$\frac{W_{3}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{3}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{3}^{\{ 1234\}}}{2}$ $\frac{W_{3}^{\{ 12346\}}}{\sqrt{5}}$$\frac{W_{3}^{\{ 123465\}}}{\sqrt{6}}$$\frac{W_{3}^{\{ 1234658\}}}{\sqrt{7}}$$\frac{W_{3}^{\{ 12346587\}}}{\sqrt{8}}$ 4 W₄ ^({1})$\frac{W_{4}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{4}^{\{ 124\}}}{\sqrt{3}}$$\frac{W_{4}^{\{ 1243\}}}{2}$ $\frac{W_{4}^{\{ 12435\}}}{\sqrt{5}}$$\frac{W_{4}^{\{ 124358\}}}{\sqrt{6}}$$\frac{W_{4}^{\{ 1243586\}}}{\sqrt{7}}$$\frac{W_{4}^{\{ 12435867\}}}{\sqrt{8}}$ 5 W₅ ^({1})$\frac{W_{5}^{\{ 14\}}}{\sqrt{2}}$ $\frac{W_{5}^{\{ 143\}}}{\sqrt{3}}$$\frac{W_{5}^{\{ 1435\}}}{2}$ $\frac{W_{5}^{\{ 14356\}}}{\sqrt{5}}$$\frac{W_{5}^{\{ 143562\}}}{\sqrt{6}}$$\frac{W_{5}^{\{ 1435628\}}}{\sqrt{7}}$$\frac{W_{5}^{\{ 14356287\}}}{\sqrt{8}}$ 6 W₆ ^({1})$\frac{W_{6}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{6}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{6}^{\{ 1345\}}}{2}$ $\frac{W_{6}^{\{ 13452\}}}{\sqrt{5}}$$\frac{W_{6}^{\{ 134526\}}}{\sqrt{6}}$$\frac{W_{6}^{\{ 1345267\}}}{\sqrt{7}}$$\frac{W_{6}^{\{ 13452678\}}}{\sqrt{8}}$ 7 W₇ ^({1})$\frac{W_{7}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{7}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{7}^{\{ 1234\}}}{2}$ $\frac{W_{7}^{\{ 12346\}}}{\sqrt{5}}$$\frac{W_{7}^{\{ 123467\}}}{\sqrt{6}}$$\frac{W_{7}^{\{ 1234678\}}}{\sqrt{7}}$$\frac{W_{7}^{\{ 12346785\}}}{\sqrt{8}}$ 8 W₈ ^({1})$\frac{W_{8}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{8}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{8}^{\{ 1345\}}}{2}$ $\frac{W_{8}^{\{ 13456\}}}{\sqrt{5}}$$\frac{W_{8}^{\{ 134562\}}}{\sqrt{6}}$$\frac{W_{8}^{\{ 1345627\}}}{\sqrt{7}}$$\frac{W_{8}^{\{ 13456278\}}}{\sqrt{8}}$ 9 W₉ ^({1})$\frac{W_{9}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{9}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{9}^{\{ 1234\}}}{2}$ $\frac{W_{9}^{\{ 12346\}}}{\sqrt{5}}$$\frac{W_{9}^{\{ 123467\}}}{\sqrt{6}}$$\frac{W_{9}^{\{ 1234675\}}}{\sqrt{7}}$$\frac{W_{9}^{\{ 12346758\}}}{\sqrt{8}}$ 10 W₁₀ ^({1})$\frac{W_{10}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{10}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{10}^{\{ 1342\}}}{2}$ $\frac{W_{10}^{\{ 13425\}}}{\sqrt{5}}$$\frac{W_{10}^{\{ 134257\}}}{\sqrt{6}}$$\frac{W_{10}^{\{ 1342576\}}}{\sqrt{7}}$$\frac{W_{10}^{\{ 13425768\}}}{\sqrt{8}}$ 11 W₁₁ ^({1})$\frac{W_{11}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{11}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{11}^{\{ 1235\}}}{2}$ $\frac{W_{11}^{\{ 12356\}}}{\sqrt{5}}$$\frac{W_{11}^{\{ 123567\}}}{\sqrt{6}}$$\frac{W_{11}^{\{ 1235674\}}}{\sqrt{7}}$$\frac{W_{11}^{\{ 12356748\}}}{\sqrt{8}}$ 12 W₁₂ ^({1})$\frac{W_{12}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{12}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{12}^{\{ 1342\}}}{2}$ $\frac{W_{12}^{\{ 13425\}}}{\sqrt{5}}$$\frac{W_{12}^{\{ 134258\}}}{\sqrt{6}}$$\frac{W_{12}^{\{ 1342587\}}}{\sqrt{7}}$$\frac{W_{12}^{\{ 13425876\}}}{\sqrt{8}}$ 13 W₁₃ ^({1})$\frac{W_{13}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{13}^{\{ 124\}}}{\sqrt{3}}$$\frac{W_{13}^{\{ 1245\}}}{2}$ $\frac{W_{13}^{\{ 12458\}}}{\sqrt{5}}$$\frac{W_{13}^{\{ 124586\}}}{\sqrt{6}}$$\frac{W_{13}^{\{ 1245863\}}}{\sqrt{7}}$$\frac{W_{13}^{\{ 12458637\}}}{\sqrt{8}}$ 14 W₁₄ ^({1})$\frac{W_{14}^{\{ 13\}}}{\sqrt{2}}$ $\frac{W_{14}^{\{ 134\}}}{\sqrt{3}}$$\frac{W_{14}^{\{ 1345\}}}{2}$ $\frac{W_{14}^{\{ 13456\}}}{\sqrt{5}}$$\frac{W_{14}^{\{ 134567\}}}{\sqrt{6}}$$\frac{W_{14}^{\{ 1345672\}}}{\sqrt{7}}$$\frac{W_{14}^{\{ 13456728\}}}{\sqrt{8}}$ 15 W₁₅ ^({1})$\frac{W_{15}^{\{ 12\}}}{\sqrt{2}}$ $\frac{W_{15}^{\{ 123\}}}{\sqrt{3}}$$\frac{W_{15}^{\{ 1235\}}}{2}$ $\frac{W_{15}^{\{ 12357\}}}{\sqrt{5}}$$\frac{W_{15}^{\{ 123574\}}}{\sqrt{6}}$$\frac{W_{15}^{\{ 1235746\}}}{\sqrt{7}}$$\frac{W_{15}^{\{ 12357468\}}}{\sqrt{8}}$

Embodiment 8

Embodiment 8 of the present invention provides a method for datatransmission. Referring to FIG. 8, in this method, a codebook foreight-antenna is stored in a UE and a base station, and the codebook foreight-antenna in this method is obtained according to the technicalsolutions provided by Embodiments 1 to 7. The method specificallyincludes the following steps.

At block 801, the base station sends a reference signal to the UE.

At block 802, the UE performs channel measurement according to thereference signal.

At block 803, the UE selects a rank, a Channel Quality Indicator (CQI),and a precoding codeword for data transmission according to a channelmeasurement result, where the precoding codeword is a certain matrixselected from a preset codebook for eight-antenna, that is, a precodingcodeword (the codeword for short) is selected.

At block 804, the UE feeds back the CQI, the rank, and a label (PMI) ofthe precoding codeword in the codebook to the base station.

At block 805, the base station selects information such as a modulationmode and a precoding matrix according to the received CQI, rank, and thelabel (PMI) of the precoding codeword in the codebook.

Specifically, the base station searches for the precoding matrix in thecodebook for eight-antenna.

At block 806, the base station uses the found precoding matrix to codedata to be sent, and sends the coded data.

At block 807, the UE receives data sent by the base station, andanalyzes the received data by using the precoding matrix selected atblock 803.

According to Embodiment 8 of the present invention, the precoding matrixstored in the UE and the base station is applicable to scenariosincluding dual-polarization strong correlation, dual-polarization weakcorrelation, single-polarization strong correlation, andsingle-polarization weak correlation, etc.

Embodiment 9

Embodiment 9 of the present invention provides a method for datatransmission. Referring to FIG. 9, the method includes the followingsteps.

At block 901, receive a label of a codeword in a codebook foreight-antenna sent by a UE;

At block 902, search for the codeword identified by the label in thecodebook for eight-antenna;

At block 903, code data to be sent by using the codeword, and send codeddata.

The codebook for eight-antenna includes at least: a rank-8 codeword foreight-antenna. The rank-8 codeword for eight-antenna is generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codewords forfour-antenna, or generated by extending rank-4 codewords foreight-antenna, where the rank-4 codeword for eight-antenna is obtainedaccording to codewords for four-antenna.

A main execution body of the above steps in the embodiment of thepresent invention may be a base station.

According to Embodiment 9 of the present invention, the rank-8 codewordfor eight-antenna is generated according to the rotation matrix foreight-antenna and the rank-4 codeword for four-antenna, or generated byextending the rank-4 codeword for eight-antenna, in which the rank-4codeword for eight-antenna is obtained according to the codeword forfour-antenna. The rank-8 codeword for eight-antenna is applicable toscenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation, etc.

Embodiment 10

Embodiment 10 of the present invention provides a method for datatransmission. Referring to FIG. 10, the method includes the followingsteps.

At block 1001, select a codeword in a codebook for eight-antenna.

At block 1002, send a label of the codeword in the codebook foreight-antenna to a base station.

The eight-antenna codebook includes at least one rank-8 codeword foreight-antenna. The rank-8 codeword for eight-antenna is generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codeword forfour-antenna, or generated by extending rank-4 codeword foreight-antenna, where the rank-4 codeword for eight-antenna is obtainedaccording to codewords for four-antenna.

The above steps in the embodiment of the present invention may beimplemented by a UE.

According to Embodiment 10 of the present invention, the rank-8 codewordfor eight-antenna is obtained according to the rotation matrix foreight-antenna and the rank-4 codeword four-antenna, or obtained byextending the rank-4 codeword for eight-antenna, in which the rank-4codeword for eight-antenna is obtained according to the codeword forfour-antenna. The rank-8 codeword for eight-antenna is applicable toscenarios including dual-polarization strong correlation,dual-polarization weak correlation, single-polarization strongcorrelation, and single-polarization weak correlation, etc.

Embodiment 11

Embodiment 11 of the present invention provides a base stationapparatus. Referring to FIG. 11, the base station apparatus includes astorage unit 1101, a receiving unit 1102, a searching unit 1103, acoding unit 1104, and a transmitting unit 1105.

The storage unit 1101 is configured to store a codebook foreight-antenna. The eight-antenna codebook includes at least one rank-8codeword for eight-antenna. The rank-8 codeword for eight-antenna isgenerated by multiplying an inverse matrix of a rotation matrix foreight-antenna with an eight-dimensional matrix formed by a rank-4codeword for four-antenna, or generated by extending rank-4 codeword foreight-antennas, where the rank-4 codeword for eight-antenna is obtainedaccording to a codeword for four-antenna.

The receiving unit 1102 is configured to receive a label of a codewordin a codebook for eight-antenna sent by a UE.

The searching unit 1103 is configured to search for the codewordidentified by the label in the codebook for eight-antenna.

The coding unit 1104 is configured to code data to be sent by using thecodeword found by the searching unit 1103.

The transmitting unit 1105 is configured to send the data coded by thecoding unit 1104.

The rank-4 codeword for eight-antenna is obtained by multiplying therank-4 codeword for four-antenna with a diagonal matrix, andconcatenating the rank-4 codeword for four-antenna and a matrix obtainedby multiplying the rank-4 codeword for four-antenna with the diagonalmatrix; or, the rank-4 codeword for eight-antenna is obtained bymultiplying a first rank-4 codeword for four-antenna with a diagonalmatrix, and concatenating a matrix obtained by multiplying the firstrank-4 codeword for four-antenna with the diagonal matrix and a secondrank-4 codeword for four-antenna.

First four columns of the rank-8 codeword for eight-antenna are therank-4 codeword for eight-antenna, and last four columns are obtained bygetting negative values of first four rows or last four rows of theeight-antenna rank-4 codeword.

Alternatively, last four columns of the rank-8 codeword foreight-antenna are the rank-4 codeword for eight-antenna, and first fourcolumns are obtained by getting negative values of first four rows orlast four rows of the rank-4 codeword for eight-antenna.

According to Embodiment 11 of the present invention, the rank-8 codewordfor eight-antenna is obtained according to a rotation matrix foreight-antenna and rank-4 codeword for four-antenna, or obtained byextending rank-4 codeword for eight-antenna, in which the rank-4codeword for eight-antenna is obtained according to a codeword forfour-antenna, thereby simplifying the complexity of the codebook design.The codeword for eight-antenna has a nested characteristic and a finitecharacter set, which may decrease the computational complexity of a CQIand reduce the storage space of the base station. The codeword foreight-antenna is applicable to scenarios including dual-polarizationstrong correlation, dual-polarization weak correlation,single-polarization strong correlation, and single-polarization weakcorrelation.

Embodiment 12

Embodiment 12 of the present invention provides a UE. Referring to FIG.12, the UE includes a storage unit 1201, a selecting unit 1202, and atransmitting unit 1203.

The storage unit 1201 is configured to store a codebook foreight-antenna. The codebook for eight-antenna includes at least onerank-8 codeword for eight-antenna. The rank-8 codeword for eight-antennais obtained by multiplying an inverse matrix of a rotation matrix foreight-antenna with an eight-dimensional matrix formed by a rank-4codeword for four-antenna; or obtained by extending rank-4 codewords foreight-antenna, where the rank-4 codeword for eight-antenna is obtainedaccording to a codeword for four-antenna.

The selecting unit 1202 is configured to select a codeword in thecodebook for eight-antenna.

The transmitting unit 1203 is configured to send a label of the selectedcodeword in the codebook for eight-antenna to a base station.

The UE further includes a receiving unit 1204, configured to receivedata sent by the base station, where the data sent by the base stationis sent after the base station uses the codeword identified by the labelto code the data to be sent; and a decoding unit 1205, configured todecode the data sent by the base station according to the selectedcodeword.

The rank-4 codeword for eight-antenna is obtained by multiplying therank-4 codeword for four-antenna with a diagonal matrix, andconcatenating the rank-4 codeword for four-antenna and a matrix obtainedby multiplying the rank-4 codeword for four-antenna with the diagonalmatrix; or, the rank-4 codeword for eight-antenna is obtained bymultiplying a first rank-4 codeword for four-antenna with a diagonalmatrix, and concatenating a second rank-4 codeword for four-antenna anda matrix obtained by multiplying the first rank-4 codeword forfour-antenna with the diagonal matrix.

First four columns of the rank-8 codeword for eight-antenna are a rank-4codeword for eight-antenna, and last four columns are obtained bygetting negative values of first four rows or last four rows of therank-4 codeword for eight-antenna; alternatively, last four columns ofthe rank-8 codeword for eight-antenna are a rank-4 codeword foreight-antenna, and first four columns are obtained by getting negativevalues of first four rows or last four rows of the rank-4 codeword foreight-antenna.

According to Embodiment 12 of the present invention, the rank-8 codewordfor eight-antenna is obtained according to the rotation matrix foreight-antenna and the rank-4 codeword for four-antenna; or obtained byextending the rank-4 codeword for eight-antenna, in which the rank-4codeword for eight-antenna is obtained according to the codeword forfour-antenna, thereby simplifying the complexity of the codebook design.The codeword for eight-antenna have a nested characteristic and a finitecharacter set, which may decrease the computational complexity of a CQIand reduce the storage space of the UE. The codeword for eight-antennais applicable to scenarios including dual-polarization strongcorrelation, dual-polarization weak correlation, single-polarizationstrong correlation, and single-polarization weak correlation, etc.

An embodiment of the present invention provides a base stationapparatus, which includes a storage unit, a receiving unit, a searchingunit, a coding unit, and a transmitting unit.

The storage unit is configured to store a codebook for eight-antenna.The codebook for eight-antenna includes at least one rank-8 codeword foreight-antenna. The rank-8 codeword for eight-antenna is generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codewords forfour-antenna; or obtained by extending rank-4 codewords foreight-antenna, where the rank-4 codeword for eight-antenna is obtainedaccording to codeword for four-antenna.

The receiving unit is configured to receive a label of a codeword in thecodebook for eight-antenna sent by a UE.

The searching unit is configured to search for the codeword identifiedby the label received by the receiving unit in the codebook foreight-antenna stored by the storage unit.

The coding unit is configured to code data to be sent by using thecodeword found by the searching unit.

The transmitting unit is configured to send the data coded by the codingunit.

The storage unit is specifically configured to store the rank-4 codewordfor eight-antenna obtained by concatenating the rank-4 codeword forfour-antenna and a matrix obtained by multiplying the rank-4 codewordfor four-antenna with a diagonal matrix, or specifically configured tostore the rank-4 codeword for eight-antenna obtained by concatenating asecond rank-4 codeword for four-antenna and a matrix obtained bymultiplying a first rank-4 codeword for four-antenna with a diagonalmatrix.

The storage unit is further configured to store the rank-8 codeword foreight-antenna obtained by using the rank-4 codeword for eight-antenna asfirst four columns of the rank-8 codeword for eight-antenna, and usingnegative values of first four rows or last four rows of the rank-4codeword for eight-antenna as last four columns of the rank-8 codewordfor eight-antenna; or specifically configured to store the rank-8codeword for eight-antenna obtained by using the rank-4 codewords foreight-antenna as last four columns of the rank-8 codeword foreight-antenna, and using negative values of first four rows or last fourrows of the rank-4 codeword for eight-antenna as first four columns ofthe rank-8 codeword for eight-antenna.

An embodiment of the present invention provides a UE, which includes astorage unit, a selecting unit, and a transmitting unit.

The storage unit is configured to store an eight-antenna codebook. Theeight-antenna codebook includes at least one rank-8 codeword foreight-antenna. The rank-8 codeword for eight-antenna is generated bymultiplying an inverse matrix of a rotation matrix for eight-antennawith an eight-dimensional matrix formed by rank-4 codewords forfour-antenna, or generated by extending rank-4 codeword foreight-antennas, where the rank-4 codeword for eight-antenna is obtainedaccording to a codeword for four-antenna.

The selecting unit is configured to select a codeword in the codebookfor eight-antenna stored by the storage unit.

The transmitting unit is configured to send a label of the codewordselected by the selecting unit in the codebook for eight-antenna to abase station.

The storage unit is specifically configured to store the rank-4 codewordfor eight-antenna obtained by concatenating the rank-4 codeword forfour-antenna and a matrix obtained by multiplying the rank-4 codewordfor four-antenna with a diagonal matrix, or specifically configured tostore the rank-4 codeword for eight-antenna obtained by concatenating asecond rank-4 codeword for four-antenna and a matrix obtained bymultiplying a first rank-4 codeword for four-antenna with a diagonalmatrix.

The storage unit is specifically configured to store the rank-8 codewordfor eight-antenna obtained by using the rank-4 codeword foreight-antenna as first four columns of the rank-8 codeword foreight-antenna, and using negative values of first four rows or last fourrows of the rank-4 codeword for eight-antenna as last four columns ofthe rank-8 codeword eight-antenna, or specifically configured to storethe rank-8 codeword for eight-antenna obtained by using the rank-4codeword for eight-antenna as last four columns of the rank-8 codewordfor eight-antenna, and using negative values of first four rows or lastfour rows of the rank-4 codeword for eight-antenna as first four columnsof the rank-8 codeword for eight-antenna.

An embodiment of the present invention provides a method for generatinga codebook, which includes:

obtaining a rotation matrix U_(rot) ⁽⁸⁾ for eight-antenna;

obtaining rank-4 codewords for four-antenna; and

obtaining a rank-8 codeword for eight-antenna by multiplying an inversematrix of the rotation matrix with an eight-dimensional matrix formed bythe rank-4 codewords for four-antenna, where the rank-8 codeword foreight-antenna are used by a base station for coding data to be sent.

A structure of the eight-dimensional matrix formed by the rank-4codewords for four-antenna is

$\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{q}^{(4)}\end{bmatrix},{{or}\begin{bmatrix}0 & X_{q}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},{{or}\text{}\begin{bmatrix}X_{p}^{(4)} & 0 \\0 & X_{p}^{(4)}\end{bmatrix}},{{or}\text{}\begin{bmatrix}0 & X_{p}^{(4)} \\X_{p}^{(4)} & 0\end{bmatrix}},$where X_(q) ⁽⁴⁾ and X_(p) ⁽⁴⁾ are respectively the rank-4 codewords forfour-antenna.

The method further includes:

switching rows of the obtained rank-8 codeword for eight-antenna.

An embodiment of the present invention further provides a method forgenerating a codebook, which includes:

obtaining a codeword for four-antenna; and

obtaining a rank-1 codeword for eight-antenna or a rank-4 codeword foreight-antenna by using the codewords for four-antenna.

As for a scenario of single-polarization strong correlation, theobtaining the codewords for four-antenna includes:

obtaining a DFT based rank-1 codeword for four-antenna by using aformula

$D_{g,{mn}}^{(N_{T})} = {{\exp\left( {j\frac{2\;\pi}{N_{T}}{m\left( {n + \frac{g}{Q}} \right)}} \right)}/N_{T,}}$where D_(g,mn) ^((N) ^(T) ⁾ is an element of an m^(th) row and an n^(th)column of a g^(th) codeword among the DFT based rank-1 codewords forfour transmit antennas, Q is the number of codewords optimized for ascenario of single-polarization strong correlation, and N_(T)=4; or

obtaining the DFT based rank-1 codeword for eight-antenna X_(p) ⁽⁸⁾ byusing a formula

$D_{g,{mn}}^{(N_{T})} = {{\exp\left( {j\frac{2\;\pi}{N_{T}}{m\left( {n + \frac{g}{Q}} \right)}} \right)}/N_{T,}}$and selecting four elements in x_(p) ⁽⁸⁾ to be elements of the DFT basedrank-1 codeword for four transmit antennas according to polarizationgroupings of antennas, where D_(g,mn) ^((N) ^(T) ⁾ is an element of them^(th) row and the n^(th) column of the g^(th) codeword among the DFTbased rank-1 codeword for eight-antenna, Q is the number of codewordsoptimized for a scenario of single-polarization strong correlation, andN_(T)=8.

The obtaining the codeword for four-antenna further includes:

extending the DFT based rank-1 codeword for four-antenna to obtain therank-4 codeword for four-antenna according to Householdertransformation; or

extending the DFT based rank-1 codeword for four-antenna to obtain therank-4 codeword for four-antenna by using a formula M_(p) ⁽⁴⁾=e_(p)×Tand a constraint condition of v_(p) ⁽⁴⁾=M_(p)(:,1), where M_(p) ⁽⁴⁾represents the rank-4 codeword for four-antenna, e_(p) is a diagonalmatrix, T is a 4×4-dimensional Unitary matrix, and v_(p) ⁽⁴⁾ representsthe DFT based rank-1 codeword for four-antenna.

The obtained codeword for four-antenna includes the DFT based rank-1codeword for four-antenna v_(p) ⁽⁴⁾.

The obtaining the rank-1 codeword for eight-antenna by using thecodeword for four-antenna includes:

obtaining the rank-1 codeword for eight-antenna by concatenating the DFTbased rank-1 codeword for four-antenna v_(p) ⁽⁴⁾ and a matrix obtainedby multiplying the DFT based rank-1 codeword for four-antenna v_(p) ⁽⁴⁾with an optimized parameter e^(jθ) ^(p.)

The obtained codeword for four-antenna includes the rank-4 codeword forfour-antenna M_(r) ⁽⁴⁾. The obtaining the rank-1 codeword foreight-antenna according to the codeword for four-antenna includes:

multiplying a rotation matrix for four-antenna with a first column ofM_(r) ⁽⁴⁾ to obtain a matrix having four rows and one column,multiplying the matrix having four rows and one column with an optimizedparameter e^(jθ) ^(r) , and concatenating a matrix obtained bymultiplying the matrix having four rows and one column with theoptimized parameter e^(jθ) ^(r) and the matrix having four rows and onecolumn to obtain the rank-1 codeword for eight-antenna as for a scenarioof dual-polarization strong correlation when the polarization groupingsof antennas are {1, 2, 5, 6} and {3, 4, 7, 8}; and/or

multiplying a rotation matrix for four-antenna with a first column ofM_(r) ⁽⁴⁾ to obtain a first matrix, multiplying the rotation matrix forfour-antenna with a first column of M_(r+R/2) ⁽⁴⁾ and the optimizedparameter e^(jθ) ^(r) to obtain a second matrix if r is in a range of 1to R/2, and concatenating the first matrix and the second matrix toobtain the rank-1 codeword for eight-antenna as for a scenario ofdual-polarization strong correlation when the polarization groupings ofantennas are {1, 2, 7, 8} and {3, 4, 5, 6}; or multiplying a rotationmatrix four-antenna with a first column of M_(r−R/2) ⁽⁴⁾ and theoptimized parameter e^(jθ) ^(r) to obtain a third matrix, concatenatingthe first matrix and the third matrix to obtain the rank-1 codeword foreight-antenna if r is in a range of (R/2)+1 to R; and/or

multiplying a rotation matrix for four-antenna with a first column ofM_(r1) ⁽⁴⁾ to obtain a fourth matrix, multiplying the rotation matrixfor four-antenna with a first column of M_(r2) ⁽⁴⁾ and an optimizedparameter e^(jθ) ^(r) to obtain a fifth matrix, and concatenating thefourth matrix and the fifth matrix to obtain the rank-1 codeword foreight-antenna as for a scenario of dual-polarization weak correlation.

The obtained codeword for four-antenna includes the rank-4 codeword forfour-antenna. The obtaining the rank-4 codeword for eight-antennaaccording to the codeword for four-antenna includes:

multiplying the rank-4 codeword for four-antenna with a diagonal matrix,and concatenating a matrix obtained by multiplying the rank-4 codewordfor four-antenna with the diagonal matrix and the rank-4 codeword forfour-antenna to obtain the rank-4 codeword for eight-antenna; and/or

multiplying a first rank-4 codeword for four-antenna with a diagonalmatrix, and concatenating a second rank-4 codeword for four-antenna anda matrix obtained by multiplying the first rank-4 codeword forfour-antenna with the diagonal matrix to obtain the rank-4 codeword foreight-antenna.

The method further includes:

using the rank-4 codeword for eight-antenna as first four columns of therank-8 codeword for eight-antenna, and using negative values of firstfour rows or last four rows of the rank-4 codeword for eight-antenna aslast four columns of the rank-8 codeword for eight-antenna; or

using the rank-4 codeword for eight-antenna as last four columns of therank-8 codeword for eight-antenna, and using negative values of firstfour rows or last four rows of the rank-4 codeword for eight-antenna asfirst four columns of the rank-8 codeword for eight-antenna.

All or a part of the steps of the method according to the embodiments ofthe present invention may be implemented by a program instructingrelevant hardware. The program may be stored in a computer readablestorage medium, such as a ROM, a magnetic disk, or an optical disk.

The method for generating a codebook and the method and apparatus fordata transmission of the embodiments of the present invention aredescribed in detail above. The principle and implementation of thepresent invention are described herein through specific examples. Thedescription about the embodiments of the present invention is merelyprovided for ease of understanding of the method and core ideas of thepresent invention. Variations and modifications may be made to thepresent invention in terms of the specific implementations andapplication scopes according to the ideas of the present invention.Therefore, the specification shall not be construed as a limit to thepresent invention.

It should be noted that, in the above embodiments of the UE and the basestation, the units are divided according to functional logic, but arenot limited to the above division as long as they can implementcorresponding functions. In addition, the specific name of eachfunctional unit is used for distinguishing, instead of limiting theprotection scope of the present invention.

Although the present invention has been described with reference tospecific features and embodiments thereof, it is evident that variousmodifications and combinations can be made thereto without departingfrom the spirit and scope of the invention. The specification anddrawings are, accordingly, to be regarded simply as an illustration ofthe invention as defined by the appended claims, and are contemplated tocover any and all modifications, variations, combinations or equivalentsthat fall within the scope of the present invention.

What is claimed is:
 1. A base station apparatus, comprising: a storageunit configured to store a codebook for an eight-antenna configuration,the codebook for the eight-antenna configuration comprising at least onerank-8 codeword for the eight-antenna configuration, the rank-8 codewordfor the eight-antenna configuration being generated by extending rank-4codewords for the eight-antenna configuration, wherein each rank-4codeword for the eight-antenna configuration is generated by creating amatrix by multiplying a first rank-4 codeword for a four-antennaconfiguration with a diagonal matrix and concatenating a second rank-4codeword for four-antenna configuration and the matrix, and wherein thefirst rank-4 codeword for the four-antenna configuration and the secondrank-4 codeword for the four-antenna configuration are the same rank-4codeword; a receiver configured to receive a label of a codeword from auser equipment (UE); and a searching unit configured to select thecodeword identified by the label from the codebook for the eight-antennaconfiguration.
 2. The base station apparatus according to claim 1,wherein one or more of the first rank-4 codeword for the four-antennaconfiguration and the second rank-4 codeword for the four-antennaconfiguration is generated according to the Formula M_(p)=e_(p)·T andtaking Formula v_(p) ⁽⁴⁾=M_(p)(:,1) as a constraint condition, wheree_(p) is a diagonal matrix, e_(p) is relevant to v_(p) ⁽⁴⁾, and v_(p)⁽⁴⁾ is a first column of M_(p), where T is any 4×4-dimensional unitarymatrix.
 3. The base station apparatus according to claim 1, wherein oneor more of the first rank-4 codeword for the four-antenna configurationand the second rank-4 codeword for the four-antenna configuration isgenerated according to a Discrete Fourier Transformation (DFT) basedrank-1 codeword for the four-antenna configuration.
 4. The base stationapparatus according to claim 1, wherein one or more of the first rank-4codeword for the four-antenna configuration and the second rank-4codeword for the four-antenna configuration is generated by performing aHouseholder transformation on a rank-1 codeword for the four-antennaconfiguration.
 5. The base station apparatus according to claim 1,wherein the rank-8 codeword for the eight-antenna configuration isgenerated by forming a first four columns of the rank-8 codeword for theeight-antenna configuration with a first rank-4 codeword for theeight-antenna configuration and forming a remaining four columns of therank-8 codeword for the eight-antenna configuration with a second rank-4codeword for the eight-antenna configuration.
 6. The base stationapparatus according to claim 1, wherein the rank-8 codeword for theeight-antenna configuration is generated by forming a first four columnsof the rank-8 codeword for the eight-antenna configuration with therank-4 codeword for the eight-antenna configuration, and forming aremaining four columns with a negative value of the rank-four codewordfor the eight-antenna configuration.
 7. A communication system,comprising: a user Equipment (UE), configured to send a label of acodeword to a base station apparatus; a base station apparatus,configured to receive the label and select the codeword identified bythe label from a stored codebook for a eight-antenna configuration, thecodebook for the eight-antenna configuration comprising at least onerank-8 codeword for the eight-antenna configuration, the rank-8 codewordfor the eight-antenna configuration being generated by extending rank-4codewords for the eight-antenna configuration, wherein each rank-4codeword for the eight-antenna configuration is generated by creating amatrix by multiplying a first rank-4 codeword for a four-antennaconfiguration with a diagonal matrix and concatenating a second rank-4codeword for four-antenna configuration and the matrix, and wherein thefirst rank-4 codeword for the four-antenna configuration and the secondrank-4 codeword for the four-antenna configuration are the same rank-4codeword.
 8. The communication system according to claim 7, wherein oneor more of the first rank-4 codeword for the four-antenna configurationand the second rank-4 codeword for the four-antenna configuration isgenerated according to the Formula M_(p)=e_(p)·T and taking Formulav_(p) ⁽⁴⁾=M_(p)(:,1) as a constraint condition, where e_(p) is adiagonal matrix, e_(p) is relevant to v_(p) ⁽⁴⁾, and v_(p) ⁽⁴⁾ is afirst column of M_(p), where T is any 4×4-dimensional unitary matrix. 9.The communication system according to claim 7, wherein one or more ofthe first rank-4 codeword for the four-antenna configuration and thesecond rank-4 codeword for the four-antenna configuration is generatedaccording to a Discrete Fourier Transformation (DFT) based rank-1codeword for the four-antenna configuration.
 10. The communicationsystem according to claim 7, wherein one or more of the first rank-4codeword for the four-antenna configuration and the second rank-4codeword for the four-antenna configuration is generated by performing aHouseholder transformation on a rank-1 codeword for the four-antennaconfiguration.
 11. The communication system according to claim 7,wherein the rank-8 codeword for the eight-antenna configuration isgenerated by forming a first four columns of the rank-8 codeword for theeight-antenna configuration with a first rank-4 codeword for theeight-antenna configuration and forming a remaining four columns of therank-8 codeword for the eight-antenna configuration with a second rank-4codeword for the eight-antenna configuration.
 12. The communicationsystem according to claim 7, wherein the rank-8 codeword for theeight-antenna configuration is generated by forming a first four columnsof the rank-8 codeword for the eight-antenna configuration with therank-4 codeword for the eight-antenna configuration, and forming aremaining four columns with a negative value of the rank-four codewordfor the eight-antenna configuration.
 13. An apparatus comprising: aprocessor; and a non-transitory computer readable storage medium coupledto the processor, with the storage medium storing programming forexecution by the processor, the programming including instructions to:provide a codebook for an eight-antenna configuration, wherein thecodebook for the eight-antenna configuration comprises at least onerank-8 codeword for the eight-antenna configuration, with the rank-8codeword for eight-antenna configuration being obtained by extendingrank-4 codewords for the eight-antenna configuration, wherein eachrank-4 codeword for the eight-antenna configuration is generated bycreating a matrix by multiplying a first rank-4 codeword forfour-antenna configuration with a diagonal matrix and concatenating asecond rank-4 codeword for a four-antenna configuration and the matrix,wherein the first rank-4 codeword for the four-antenna configuration andthe second rank-4 codeword for the four-antenna configuration are thesame rank-4 codeword; receive a label of a codeword from a userequipment (UE); and select the codeword identified by the label from thecodebook for the eight-antenna configuration.
 14. The apparatusaccording to claim 13, wherein the rank-8 codeword for the eight-antennaconfiguration is generated by forming a first four columns of the rank-8codeword for the eight-antenna configuration with a first rank-4codeword for the eight-antenna configuration and forming a remainingfour columns of the rank-8 codeword for the eight-antenna configurationwith a second rank-4 codeword for the eight-antenna configuration. 15.The apparatus according to claim 13, wherein the rank-8 codeword for theeight-antenna configuration is generated by forming a first four columnsof the rank-8 codeword for the eight-antenna configuration with therank-4 codeword for the eight-antenna configuration, and forming aremaining four columns with a negative value of the rank-four codewordfor the eight-antenna configuration.
 16. The apparatus according toclaim 13, wherein one or more of the first rank-4 codeword for thefour-antenna configuration and the second rank-4 codeword for thefour-antenna configuration is generated according to the FormulaM_(p)=e_(p)·T and taking Formula v_(p) ⁽⁴⁾=M_(p)(:,1) as a constraintcondition, where e_(p) is a diagonal matrix, e_(p) is relevant to v_(p)⁽⁴⁾, and v_(p) ⁽⁴⁾ is a first column of M_(p), where T is any4×4-dimensional unitary matrix.
 17. The apparatus according to claim 13,wherein one or more of the first rank-4 codeword for the four-antennaconfiguration and the second rank-4 codeword for the four-antennaconfiguration is generated according to a Discrete FourierTransformation (DFT) based rank-1 codeword for the four-antennaconfiguration.
 18. The apparatus according to claim 13, wherein one ormore of the first rank-4 codeword for the four-antenna configuration andthe second rank-4 codeword for the four-antenna configuration isgenerated by performing a Householder transformation on a rank-1codeword for the four-antenna configuration.